1. Field of the Invention
The present invention relates to a field of liquid crystal display technology, in particular to a backlight module and a display device.
2. Description of the Prior Art
Currently, liquid crystal display (LCD) is a commonly used flat panel display, and it includes a backlight module as an important part for serving as a light source for a liquid crystal panel during the operation of the LCD. According to different incident positions of the light, the backlight module includes side-type backlight module and direct-type backlight module. For the direct-type backlight module, a light source such as a CCFL (Cold Cathode Fluorescent Lamp) or LED (Light Emitting Diode) is positioned behind the liquid crystal panel, so as to directly provide the area light to the liquid crystal panel. For the side-type backlight module, a LED light bar is positioned at an edge of a back plate of the liquid crystal panel. The light from the LED light bar enters a light guide plate (LGP) from a light-entering surface at a side of the LGP, emerges out from a light-exiting surface of the LGP upon reflection and diffusion, and then passes through optical films to form the area light to be provided to the liquid crystal panel.
The traditional side-type backlight module comprises a outer frame, a rubber frame, a back plate, a LED light bar and a light guide plate, and so on. FIG. 1 is a side view of the traditional backlight module. As shown in FIG. 1, the light guide plate 100′ of the side-type backlight module 10′ is positioned at a side of the liquid crystal panel that receives the incident light. The LED light bar 200′ is positioned at a edge of the light guide plate 100′, i.e., facing a light-entering surface 101′ of the light guide plate 100′. There is a gap G′ between the LED light bar 200′ and the light guide plate 100′. In teams of thermology, the larger the gap G′, the better. In terms of optics, if the gap G′ is too large, a part of the light from the LED light bar 200′ will reach the rubber frame 300′ arranged at an upper side of the LED light bar 200′ and the light guide plate 100′, rather than enter the light-entering surface 101′ of the light guide plate 100′. As a result, the utilization rate of the light from the LED light bar 200′ will be low, and a brightness loss will be caused. FIG. 2 is an enlarged view of the LED light bar 200′ in the traditional backlight module 10′ in FIG. 1 viewed along an arrow A. As shown in FIG. 2, usually the LED light bar 200′ includes a PCB plate 202′ and a plurality of LED lamps 201′ arranged at intervals. Hence, the light intensity is high at the place where the LED lamps 201 are located, while the light intensity is low at intervals between the adjacent LED lamps. As a result, an uneven light intensity will be achieved and hot spots will easily be caused.
FIG. 3 is a side view of another backlight module in the prior art. As shown in FIG. 3, a reflector 400′ parallel to a light-exiting surface 102′ of the light guide plate 100′ is arranged at an upper side of a gap between the LED light bar 200′ and the light guide plate 100′, so as to reflect the light from the LED light bar 200′ to the light-entering surface 101′ of the light guide plate 100′, thereby to meet the requirement of a large gap G′ between the LED light bar 200′ and the light guide plate 100′ in terms of thermology, and to reduce the light loss. However, such a structure, on one hand, cannot solve the problem of uneven light intensity due to the distribution of the LED lamps at intervals as well as the hot spots generated thereby, and on the other hand, cannot solve the problem of light loss due to the escape of a part of the light from the slit between the reflector 400′ and the light guide plate 100′.